Fuel products, such as oil, petrochemicals, and other substances useful for the production of petrochemicals are increasingly in demand. By 2030, energy demand, primarily in the form of oil and gas, is projected to increase by 45%. In many countries, there is a disparity between oil use and oil production. For example, it is estimated that during the year 2008, the United States consumed approximately 19 million barrels of oil per day while producing only about 8 million barrels per day. This disparity is projected to markedly increase in the future as domestic production plateaus or declines. For economic and national security reasons, there is a renewed emphasis on the development of alternative sources of hydrocarbons other than fossil fuels.
In addition, the burning of fossil fuels has been associated with increasing levels of carbon dioxide in the earth's atmosphere. This increase in carbon dioxide has, in turn, been associated with a gradual increase in the earth's temperature. By some estimates, the average global temperature may rise as much as 6° C. by the end of the century if carbon emissions are not reduced. Such a global temperature rise could have a substantial effect on human civilization due to such things as coastal flooding and crop failures. As a result, there has been increased interest in developing energy resources that are carbon neutral or result in greatly reduced net CO2 production. Also, as fossil fuels become technically more difficult to obtain, public awareness regarding pollution and environmental hazards in the production of fossil fuels has increased.
As a result, there has been a growing interest and need for alternative methods to produce fuel products. Biomass, and in particular lipid containing microorganisms, provides an alternative source of hydrocarbons for use as fuels. Photosynthetic microorganisms, such as photosynthetic microalgae and photosynthetic bacteria, are especially useful due to their ability to remove carbon dioxide from the atmosphere and the fact that they do not directly compete with food production for resources.
Algae are highly adaptable plants that are capable of rapid growth under a wide range of conditions. Most algal species are adapted for growth in an aqueous environment and can be grown in liquid media using light as an energy source. The ability to grow algae on a large scale in an outdoor setting, in ponds or other open or closed containers, using sunlight for photosynthesis, enhances their utility for bioproduction of energy, environmental remediation, and carbon fixation.
Critical to the use of aquatic microorganisms for the production of fuels, is the ability to efficiently and economically recover the oil from the organisms. Given that the majority of photosynthetic algae and bacteria are aquatic, it is preferable that the method be suitable for recovering oil from biomass with a high water content.